1

Irrigation Water Management (IWM) is applying wateraccording to crop needs in an amount that can be stored

in the plant root zone of the soil.

The "feel and appearance method" is one of severalirrigation scheduling methods used in IWM. It is away of monitoring soil moisture to determine whento irrigate and how much water to apply. Applyingtoo much water causes excessive runoff and/ordeep percolation. As a result, valuable water is lostalong with nutrients and chemicals, which mayleach into the ground water.

The feel and appearance of soil vary with textureand moisture content. Soil moisture conditions canbe estimated, with experience, to an accuracy ofabout 5 percent. Soil moisture is typically sampledin I-foot increments to the root depth of the crop atthree or more sites per field. It is best to vary thenumber of sample sites and depths according tocrop, field size, soil texture, and soil stratification.For each sample the "feel and appearance method"involves:

Available Water Capacity (AWC) is the portion ofwater in a soil that can be readily absorbed by plantroots of most crops.

Soil Moisture Deficit (SMD) or Depletion is theamount of water required to raise the soil-watercontent of the crop root zone to field capacity.

1. Obtaining a soil sample at the selected depthusing a probe, auger, or shovel;

2. Squeezing the soil sample firmly in your handseveral times to form an irregularly shaped "ball";

3. Squeezing the soil sample out of your handbetween thumb and forefinger to form a ribbon;

4. Observing soil texture, ability to ribbon, firmnessand surface roughness of ball, water glistening,loose soil particles, soil/water staining on fingers,and soil color. [Note: A very weak ball will disinte-grate with one bounce of the hand. A weak balldisintegrates with two to three bounces;

5. Comparing observations with photographs and/orcharts to estimate percent water available andthe inches depleted below field capacity.

Example:

Sample USDA AWC*for Soil Moisture Percent Depth Zone Texture Zone Delpetion** Depletion

6” 0-12" sandy loam 1.4" 1.0" 70

18" 12-24" sandy loam 1.4" .8" 55

30" 24-36" loam 2.0" .8" 40

42" 36-48" loam 2.0" .5" 256.8" 3.1"

Result: A 3.1" net irrigation will refill the root zone.* Available Water Capacity** Determined by “feel and appearance method”

Estimating Soil Moistureby Feel and AppearanceEstimating Soil Moistureby Feel and Appearance

2

Appearance of fine sand and loamy fine sand soilsat various soil moisture conditions.

Available Water Capacity0.6-1.2 inches/foot

Percent Available: Currently available soil mois-ture as a percent of available water capacity.

In/ft. Depleted: Inches of water currently needed torefill a foot of soil to field capacity.

0-25 percent available1.2-0.5 in./ft. depleted

Dry, loose, will hold together if not disturbed, loosesand grains on fingers with applied pressure. (Notpictured)

25-50 percent available0.9-0.3 in./ft. depleted

Slightly moist, forms a very weak ball with well-defined finger mark

50-75 percent available0.6-0.2 in./ft. depleted

Moist, forms a weak ball with loose and aggregatedsand grains on fingers, darkened color, moderatewater staining on fingers, will not ribbon.

75-100 percent available0.3-0.0 in./ft. depleted

Wet, forms a weak ball, loose and aggregated sandgrains remain on fingers, darkened color, heavywater staining on fingers, will not ribbon

100 percent available0.0 in./ft. depleted (field capacity)

Wet, forms a weak ball, moderate to heavy soil/water coating on fingers, wet outline of soft ballremains on hand. (Not pictured)

3

Appearance of sandy loam and fine sandy loam soilsat various soil moisture conditions.

Available WaterCapacity1.3-1.7 inches/foot

Percent Available: Currently available soil mois-ture as a percent of available water capacity.

In/ft. Depleted: Inches of water currently needed torefill a foot of soil to field capacity.

100 percent available0.0 in./ft. depleted (field capacity)

Wet, forms a soft ball, free water appears briefly onsoil surface after squeezing or shaking, medium toheavy soil/water coating on fingers. (Not pictured)

75-100 percent available0.4-0.0 in./ft. depleted

Wet, forms a ball with wet outline left on hand, lightto medium staining on fingers, makes a weakribbon between the thumb and forefinger.

50-75 percent available0.9-0.3 in./ft. depleted

Moist, forms a ball with defined finger marks, verylight soil/water staining on fmgers, darkened color,will not slick.

25-50 percent available1.3-0.7 in/ft. depleted

Slightly moist, forms a weak ball with defined fingermarks, darkened color, no water staining on fingers,grains break away.

0-25 percent available 17-1.0 in/ft. depleted

Dry, forms a very weak ball, aggregated soil grainsbreak away easily from ball. (Not pictured)

4

Appearance of sandy clay loam, loam, and silt loam soilsat various soil moisture conditions.

Available WaterCapacity1.5-2.1 inches/foot

Percent Available: Currently available soil mois-ture as a percent of available water capacity.

In/ft. Depleted: Inches of water currently needed torefill a foot of soil to field capacity.

0-25 percent available2.1-1.1 in./ft. depleted

Dry, soil aggregations break away easily, no stain-ing on fingers, clods crumble with applied pressure.(Not pictured)

25-50 percent available1.6-0.8 in./ft. depleted

Slightly moist, forms a weak ball with rough sur-faces, no water staining on fingers, few aggregatedsoil grains break away.

50-75 percent available1.1-0.4 in./ft. depleted

Moist, forms a ball, very light staining on fingers,darkened color, pliable, forms a weak ribbon be-tween the thumb and forefinger.

75-100 percent available0.5-0.0 in/ft. depleted

Wet, forms a ball with well-defined finger marks,light to heavy soil/water coating on fingers, ribbonsbetween thumb and forefinger.

100 percent available0.0 in/ft. depleted (field capacity)

Wet, forms a soft ball, free water appears briefly onsoil surface after squeezing or shaking, medium toheavy soil/water coating on fingers. (Not pictured)

5

0-25 percent available2.4-1.2 in/ft. depleted

Dry, soil aggregations separate easily, clods arehard to crumble with applied pressure. (Not pic-tured)

25-50 percent available1.8-0.8 in/ft. depleted

Slightly moist, forms a weak ball, very few soilaggregations break away, no water stains, clodsflatten with applied pressure.

50 - 75 percent available1.2-0.4 in./ft. depleted

Moist, forms a smooth ball with defined fingermarks, light soil/water staining on fingers, ribbonsbetween thumb and forefinger.

75-100 percent available0.6-0.0 in./ft. depleted

Wet, forms a ball, uneven medium to heavy soil/water coating on fingers, ribbons easily betweenthumb and forefinger.

100 percent available0.0 in./ft. depleted (field capacity)

Wet, forms a soft ball, free water appears on soilsurface after squeezing or shaking, thick soil/watercoating on fingers, slick and sticky. (Not pictured)

Appearance of clay, clay loam, and silt clay loam soilsat various soil moisture conditions.

Available WaterCapacity1.6-2.4 inches/foot

Percent Available: Currently available soil mois-ture as a percent of available water capacity.

In/ft. Depleted: Inches of water currently needed torefill a foot of soil to field capacity.

6

Guidelines for Estimating Soil Moisture Conditions

Coarse Texture- Moderately Coarse Texture Medium Texture - Fine Texture-Fine Sand and Sandy Loam and Sandy Clay Loam, Loam, Clay, Clay Loam, or

Loamy Fine Sand Fine Sandy Loam and Silt Loam Silty Clay Loam

Available Water Capacity (Inches/Foot)

0.6-1.2 1.3-1.7 1.5-2.1 1.6 -2.4

AvailableSoil Moisturre Soil Moisture Deficit (SMD) in inches per foot when the feel and appearance of the soil are as described.

Percent

Dry, forms a very weak ball,aggregated soil grainsbreak away easily from ball.

SMD 1.7 -1.0

Dry, loose, will hold togetherif not disturbed, loose sandgrains on fingers withapplied pressure.

SMD 1.2-0.5

Dry. Soil aggregations breakaway easily. no moisturestaining on fingers, clodscrumble with appliedpressure.

SMD 2.1-1.1

Dry, soil aggregationseasily separate, clods arehard to crumble withapplied pressure

SMD 2.4-1.2

Slightly moist, forms a veryweak ball with well-definedfinger marks, light coating ofloose and aggregated sandgrains remain on fingers.

SMD O.9-0.3

Slightly moist, forms a weakball with defined fingermarks, darkened color, nowater staining on fingers,grains break away.

SMD 1.3-0.7

Slightly moist, forms a weakball with rough surfaces, nowater staining on fingers,few aggregated soil grainsbreak away.

SMD1.6-0.8

Slightly moist, forms a weakball, very few soil aggrega-tions break away, no waterstains, clods flatten withapplied pressure

SMD 1.8-0.8

0-25

25-50

50-75

75-100

FieldCapacity(100 %)

Moist, forms a weak ball withloose and aggregated sandgrains on fingers, darkenedcolor, moderate waterstaining on fingers, will notribbon.

SMD O.6-0.2

Moist, forms a ball withdefined finger marks. verylight soil/water staining onfingers. darkened color, willnot slick.

SMD O.9-0.3

Moist, forms a ball, verylight water staining onfingers, darkened color,pliable, forms a weakribbon between thumb andforefinger.

SMD 1.1- 0.4

Moist. forms a smooth ballwith defined finger marks,light soil/water staining onfingers, ribbons betweenthumb and forefinger.

SMD l.2-0.4

Wet, forms a weak ball,loose and aggregated sandgrains remain on fingers,darkened color, heavy waterstaining on fingers, will notribbon.

SMD O.3-0.0

Wet, forms a ball with wetoutline left on hand, light tomedium water staining onfingers, makes a weakribbon between thumb andforefinger.

SMD O.4-0.0

Wet, forms a ball with welldefined finger marks, light toheavy soil/water coating onfingers, ribbons between ,thumb and forefinger.

SMD O.5 -0.0

Wet, forms a ball, unevenmedium to heavy soil/watercoating on fingers, ribbonseasily between thumb andforefinger.

SMD O.6-0.0

Wet, forms a weak ball,moderate to heavy soil/water coating on fingers,wet outline of soft ballremains on hand.

SMD 0.0

Wet, forms a soft ball, freewater appears briefly on soilsurface after squeezing orshaking,medium to heavysoil/water coating onfingers.

SMD 0.0

Wet, forms a soft ball, freewater appears briefly on soilsurface after squeezing orshaking, medium to heavysoil/water coating on fingers.

SMD 0.0

Wet, forms a soft ball, freewater appears on soilsurface after squeezing orshaking, thick soil/watercoating on fingers, slick andsticky.

SMD 0.0

The United States Department of Agriculture (USDA) prohibits discrimination in its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and maritalor family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact the USDA’sTARGET Center at 202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC, 20250-9410 or call 202-720-5964 (voice or TDD). USDA isan equal opportunity provider and employer.

April 1998